3. Combining gates (2)
Let us consider combining three logic gates to end up with a single output Q. This is the drawing:
Task: Write down the boolean expression for this.
Step 1: The output of the AND gate is $$ z = A.B$$ which is feeding into the NAND gate.
Step 2: The output of the OR gate is $$ y = C + D$$
Step 3: These are the inputs to the NAND gate, so write each term then add a dot between terms and an overall bar
$$Q=\overline{(C+D) . (A.B)}$$
which is the answer.
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: How to build boolean expressions